Whether you develop web applications or mobile apps, the OAuth 2.0 protocol will save a lot of headaches. This concise introduction shows you how OAuth provides a single authorization technology across numerous APIs on the Web, so you can securely access users’ data—such as user profiles, photos, videos, and contact lists—to improve their experience of your application.

Through code examples, step-by-step instructions, and use-case examples, you’ll learn how to apply OAuth 2.0 to your server-side web application, client-side app, or mobile app. Find out what it takes to access social graphs, store data in a user’s online filesystem, and perform many other tasks.